An Image Decoder Based on IImgCtx

// ImgViewerView.cpp : implementation of the CImgViewerView class
//

#include "stdafx.h"
#include "ImgViewer.h"

#include "ImgViewerDoc.h"
#include "ImgViewerView.h"
#include "WndImgCtx.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CImgViewerView

IMPLEMENT_DYNCREATE(CImgViewerView, CScrollView)

BEGIN_MESSAGE_MAP(CImgViewerView, CScrollView)
	//{{AFX_MSG_MAP(CImgViewerView)
	ON_WM_ERASEBKGND()
	//}}AFX_MSG_MAP
	// Standard printing commands
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CImgViewerView construction/destruction

CImgViewerView::CImgViewerView()
{
	// TODO: add construction code here
	m_hBitmap = NULL;
}

CImgViewerView::~CImgViewerView()
{
	CleanUp();
}

BOOL CImgViewerView::PreCreateWindow(CREATESTRUCT& cs)
{
	// TODO: Modify the Window class or styles here by modifying
	//  the CREATESTRUCT cs

	return CScrollView::PreCreateWindow(cs);
}

/////////////////////////////////////////////////////////////////////////////
// CImgViewerView drawing

void CImgViewerView::OnDraw(CDC* pDC)
{
	CImgViewerDoc* pDoc = GetDocument();
	ASSERT_VALID(pDoc);
	// TODO: add draw code for native data here

	if (m_hBitmap)
	{
		HDC hMemDC = CreateCompatibleDC(pDC->GetSafeHdc()); 
		if (hMemDC)
		{
			// select new bitmap into memory DC 
			HBITMAP hOldBitmap = (HBITMAP)SelectObject(hMemDC, m_hBitmap);

			// show it
			CSize sizeTotal;
			::GetBitmapDimensionEx(m_hBitmap, &sizeTotal);
			::BitBlt(pDC->GetSafeHdc(), 0, 0, sizeTotal.cx, sizeTotal.cy,
				hMemDC, 0, 0, SRCCOPY);

			// select old bitmap back into memory DC and get handle to bitmap
			SelectObject(hMemDC, hOldBitmap); 

			DeleteDC(hMemDC); 
		}
	}
}

void CImgViewerView::OnInitialUpdate()
{
	CScrollView::OnInitialUpdate();

	CSize sizeTotal;
	sizeTotal.cx = sizeTotal.cy = 0;
	
	CleanUp();

	CImgViewerDoc* pDoc = GetDocument();
	CString strPath = pDoc->GetPathName();
	if (!strPath.IsEmpty())
		m_hBitmap = GetBitmapFromFile(strPath);

	if (m_hBitmap)
		GetBitmapDimensionEx(m_hBitmap, &sizeTotal);
	
	SetScrollSizes(MM_TEXT, sizeTotal);

	Invalidate();
	UpdateWindow();
}

/////////////////////////////////////////////////////////////////////////////
// CImgViewerView diagnostics

#ifdef _DEBUG
void CImgViewerView::AssertValid() const
{
	CScrollView::AssertValid();
}

void CImgViewerView::Dump(CDumpContext& dc) const
{
	CScrollView::Dump(dc);
}

CImgViewerDoc* CImgViewerView::GetDocument() // non-debug version is inline
{
	ASSERT(m_pDocument->IsKindOf(RUNTIME_CLASS(CImgViewerDoc)));
	return (CImgViewerDoc*)m_pDocument;
}
#endif //_DEBUG

/////////////////////////////////////////////////////////////////////////////
// CImgViewerView message handlers

void CImgViewerView::CleanUp()
{
	if (m_hBitmap)
	{
		DeleteObject(m_hBitmap);
		m_hBitmap = NULL;
	}
}

BOOL CImgViewerView::OnEraseBkgnd(CDC* pDC) 
{
	// TODO: Add your message handler code here and/or call default
	CBrush br;
	br.CreateSolidBrush(RGB(0, 0, 0));
	FillOutsideRect(pDC, &br);
	br.DeleteObject();

	return TRUE;
}